1. Field of the Invention
The present invention relates to a virtual machine system, and more particularly to measurement and display of a central processing unit (CPU) busy ratio of a guest operating system (OS) running on a logical partition (LPAR).
2. Description of the Related Art
In a virtual machine system, a single physical machine is divided into a plurality of logical partitions by a hypervisor; each of machine resources such as a CPU, a main memory and an input/output (I/O) interface is assigned to each of the logical partitions; and an OS runs on each of the logical partitions. Each of these OSs is called a guest OS. The execution of the guest OSs is controlled by a monitor program called a hypervisor.
The guest OS runs in the same way as general OSs from a logical perspective. A CPU performance monitor program running on the guest OS is executed in the same way as general performance monitor programs. The performance monitor program running on the guest OS measures a CPU busy ratio without the assumption that a physical CPU is assigned to the LPAR by the hypervisor or deassigned. Therefore, when the CPU assigned to the guest OS is fully utilized, the CPU busy ratio is displayed as 100% even if 50% of physical CPU resources are assigned to the LPAR.
In order to measure the physical CPU busy ratio (50% in the above case) of the guest OS in a virtual machine environment, it is necessary that the performance monitor program running on the guest OS and the performance monitor program of the hypervisor are executed for the same measurement interval and that both measurement results be multiplied.
For example, JP-A-2003-157177 discloses a virtual machine system in which the load of an OS running on each LPAR is measured, and in which an assignment of each of machine resources to each LPAR is dynamically changed based on the measured OS load and setting information according to a workload to be executed on each OS.